New product development is an important ongoing process for marketing management. It involves creating new product ideas, evaluating their sales and profit potential, designing and testing production, and marketing the product. The main stages are generating new ideas, screening ideas, assessing commercial feasibility, designing and evaluating the product, test marketing, and launching the product. Products can fail for reasons such as a faulty initial idea, poor design that doesn't meet customer needs, higher than expected production costs, inadequate understanding of market changes, insufficient promotion, incorrect pricing, or issues with packaging. Careful consideration at each stage of development is needed to avoid product failure.